Adjustable plaster ground



April 5, 1960 R. w. NEN 2,931,105

ADJUSTABLE PLAs'rER GROUND Filed Haren 19, 1955 2 sheets-sheet 1 1 INVENToR.. 1 ,4r/6 4 ,r/s Raaf/5r won/yin g o y HTTORNEY April 5, 1960 R. wi DANEN 2,931,105

ADJUSTABLE- PLASTER GROUND n Filed March 19, 1956 2 Sheets-Sheet 2 1N VEN TOR.

R055?? won/Wsw BY HTTRN'Y United States This invention relates to plaster trim guides, and more particularly to a plaster trim guide comprising a plurality of overlapping sections relatively slidable upon each other.

This application is a continuation-in-part of a copending application Serial No. 443,667, filed July l5, 1954, now abandoned.

The purpose of this invention is to provide an improved plaster trim guide that is composed of a plurality of coasting slidable sections which are interchangeably useable at random, and that eliminates inoperativeness thereof caused by the interference of foreign matter thereon, such as hardened plaster.

It is an object of this invention to provide a plaster trim guide that is adjustable lengthwise to accommodate wall openings of different size throughout a wide range of adjustment.

It is another object to provide a that is removable and re-useable.

It is a further object of this invention to provide a plaster trim guide that is designed to be easily cleaned with a minimum of effort.

It is still another object to provide a plaster trim guide having anti-clogging coacting lguiding means.

It is yet another object of this invention to provide a ribbed plaster ground having one or both ends beveled.

Still a further object is to provide cambered type of plaster ground, such as one bent or convex, or the like, adapted for a tensioned t at the studding edges.

Yet a further object of this invention is the provision of a cambered or raised-center type of ground, whereby the laterally projecting edge margins deviate from the plane of the studding face to provide relief, rake or inclined clearance angle of the plaster formation, thereby to prevent breaking away of edge portion plaster when the finished door frame is being wedged into position; and

Another object is to provide a wall opening corner structure embodying adjustable plaster grounds.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which like reference numerals designate like parts throughout the figures thereof and wherein:

Fig. 1 shows an isometric view of one section of the plaster trim guide;

Fig. 2 is an isometric view of a section of the plaster trim guide, complementary to the section shown in Fig. l;

Fig. 3 illustrates an isometric view of a door opening showing the plaster trim guide applied to the frame thereof; v

Fig. 4v is a modication of Figs. 1 and 2, in cross-section, showing the application of open triangular ribs;

Fig. 5 is a modification of Figsyl and 2, in cross-section, showing the application of open trapezoidal ribs;

plaster trim v guide "Patent Figs. 6 and 7 are isometric views, illustrating a modied form of the invention, showing companion plaster ground sections or strips having an end thereof beveled;

Fig. 8 is a front elevation view of a rough framed'V door opening, showing the modified form of the plaster ground disclosed in Figs. 6 and 7 applied to the face margins of said frame, particularly showing the corners and overhead arrangement of ground elements;

Fig. 9 is an exploded view of a corner arrangement of Fig. 8, showing the receivability of the overhead unbeveled rib end into the side beveled rib end cut-out;

Figs. 10 and 11 are isometric views illustrating a second modification of the invention, showing narrow single rib companion strips vhaving both ends beveled;

Fig. 12 is a cross section view of another modification showing a cambered ground formed convex, with a raisedcenter to provide a tensioned t against the studding edges;

Fig. 13 is a cross-section view, showing the cambered ground of Fig. 12 applied to a studding, thereby providing a tensioned tit against the studding edges; and showing the lateral projecting edges of the ground deviating from the plane of the face of the studding thereby pro- Viding relief or an inclined clearance angle for the plaster to be formed thereagainst;

Fig. 14 is a cross-Section View of a further modification showing a cambered or raised-center plaster ground, for providing tensioning against the studding edges, and relief of the plaster to be formed thereagainst.

Fig. 15 is a cross-section view, showing the cambered ground of Fig. A14 applied to a studding, thereby providing tensioning and relief as described n the description of Fig. 13, above;

Fig. 16 is a cross-section view of still another cambered or bent ground, the bending being along the longitudinal axis of the strip; and

Fig. 17 is a cross-section view of a further cambered or convex type of ground.

Referring now to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, there is shown a tlat ground strip 9 comprising a pair of overlapping plate sections 10 and 13 adapted for relative sliding movement lengthwise.

Section 10 is provided with a pair of spaced longitudinal open ribs 11 and 12 pressed and formed from the plate, on one side thereof.

A substantially similar formed complementary plate section 13, of equal, lesser or greater length, having ribs 14 and 15, is adapted to be slidably mounted on plate section 10 with the corresponding ribs mutually slidably engaged.

Said ribs can be of the wide open curvilinear or arcuate cross-section as shown in Fig. 1 and 2, or the open triangular or open trapezoidal type as shown in Figs. 4 and 5, respectively, or the like. The open arcuate rib is preferred because of the ease of cleaning thereof, that is, the ease of cleaning foreign matter therefrom, such as plaster, which has hardened thereon. Because of the wide open construction of the ribs, it is obvious that all rib surfaces thereof can be conveniently reached and easily scraped clean of any foreign matter lodged therein or thereon. The open anti-clogging construction of the ribs is particularly meritorious.

Said plate section 1i) is provided with a series of uniformly spaced 'apertures 16, disposed along the longitudinal axis thereof, and adapted to snugly receive nails. Quarter inch spacing, preferred but not necessary, provides practical increments of adjustment.

The complementary plate section 13 is also provided with a series of similar uniformly spaced apertures 17, disposed along the longitudinal axis thereof, and adapted to snugly receive said nails.

With the series of apertures thus disposed and spaced, the desired lengthwise adjustments can be realized by sliding the plates one over the other, guided longitudinally by the engaged ribs, andA placing a double-headed nail 20 in the properly selected registering apertures, and driving it into the frame, hereinafter described for securement thereto.

' The plates l0 and 13 are preferably constructed of a Suitable metal, plastic, or other material yof sufficient strength and stiffness to withstand the working of plaster thereagainst and to support the edge of the plaster which abuts thereagainst. it has been observed that aluminum plates of approximately to 20 gauge thickness serve very well, but the invention is not limited vto said gauge range.

The plates should be constructed of lengths less than the length of the maximum normal length of the desired opening, to allow for the time saving convenience of trim guide adjustability.

For random interchangeability, it is preferred, though not necessary, that the plates it? and 13 be formed of the same dies, and therefore will have the same configuration; Flexibility in the plate material used, if desired, thoughV not necessary, to allow drawing the ribs into substantial conformance with each other, despite non-allowance for precise engagement thereof. Thin sheets of flexible material, having rib cross-sections as described above, can be easily drawn into practical conformance with each other.

When associated plates of the same configuration are used, the central body portions, and side portions, of the overlaying plates, are space related from ,each other by an amount equal to the thickness of the plates. To drive the nail 2u home under this circumstance, drawing the plates into contact with eachother at the nail Zone, would cause the topplate 13 to bow slightly, resulting in the outer edge portions thereof warping away from the cor` responding edge portions of the associated lower plate 19.' This objectionable situation can be avoided by not driving said nail 2? home, that is, to drive its head only to a point of contact with said top plate 13, thereby leaving the body and edge portions of the plates in their original spaced relation. This arrangement will suiciently secure the plates to the frame, and` be suitable, for all practical purposes.

Should the top plate i3 be made from a die different from the die used in forming plate 1i), to provide precise matching and surface engagement thereof, over all surfaces, the above bowing and warping would of coursebe eliminated. However, the convenience of random inter-V changeability would be sacriced.

The plates should be of a width suicient to cover an edge of a frame opening and to project laterally onopposite sides of said edge to receive the desired thickness of4 plaster thereagainst.

The plates should be constructed of lengths less than the length of an edge of the opening to be accommodated. This lesser length obtains the desired lengthwise adjustment and extension, by sliding one plate over the other, to cover an edge to be accommodated. This obviates the necessity of cutting sections to lit. Obviously, plates of diifering lengths can be associ-ated in use, as well as plates of equal lengths.

Obviously, a series of such plates 1t) and 13 can be used to cover an opening edge having a length very much greater than any pair of plates. i

Operation: In applying the trim guide plates to a wall opening such as a door opening bounded by studding 18 and 19, and header 21, one of the plates, say plate 10, is

disposed vertically against the face of studding 1S, with Y the ribs 11 and i2 projecting outwardly, and the side edge portions of the plates projecting laterally equal distances on opposite sides of the studding 1S to accommodate the desired thickness of plaster 22 and lathing 23. Nails 24 and 2.5 are driven in suitable apertures to secure said positioned plate l@ to-said studding 18.

Plate 13 is then superimposed uponplate 1t), with the ribs thereof in engagement, and slid upwardly, guided by the ribs, until it abuts against the header 21. Nail 20 is then inserted into a pair of registering apertures, registration being occasioned by a slight retraction of plate 13, and is then driven into stud 1S to secure the plate 13 thereto. An additional nail 26 is driven in a suitable aperture in the upper end portion of plate 13 to further secure said plate 13 to the studding 18. Obviously, the plate 13, guided longitudinally by the lower plate 10, becomes disposed, relative to the studding 18, so that the side edge portions of the plate 13 also project laterally equal distances on opposite sides of the studding.

Obviously, plates of accommodating length can be applied similarly to the header 2.

When the plaster is applied to the wall lathing, the side edges of the plates provide a true and straight trim edge for' guiding the plasterer in his work, so that smooth, plane surfaces can be given to the plaster as it is, applied at the edges of openings.

After the plaster has been applied about the door frame, and sufficiently dried, the plates 10 and x13 can be easily removed by withdrawing the nails with a claw hammer engaged under the double-headed nails, and the plate sections re-used.

Figs. 6 and 7 show a pair of complementary ground sections or strips modified by the inclusion of beveled end portions. j

Complementary superposable sections or strips 31 and 32, generally similar to complementary sections 10 and 13, are each provided with a pair of V-shaped corrugations or longitudinal ribs 33, 34, 35 and 36, mutually slidably engageable for relative lengthwise movement. Said open faced guide ribs are spaced from the side edges of the strips by side margins, and the ribs are disposed symmetrically about the longitudinal axis of the strips. The strips are of equal width, and flat; or they maybe of the cambered Vor raised-center type as shown in Figs. 12 to 17.

Both strips are provided with a series of spaced aper tures 30 and 37, disposed along the longitudinal axes thereof, respectively, for the reception of nails therein. The apertures are preferably variably spaced at M1, 1%", '1/2", 1A", 3/s", 1/z" centers, successively repeated. Said series of predeterminately spaced apertures in each strip is operative to selectively register as the strips are guided relative to each other.

The strips are of thin sheet steel material, or the like, about 22 gauge preferred, and reasonably flexible. However, the invention is not limited to the above gauge thickness. Flexibility may result from the inherent characteristic of the material used, or from the thickness factor. Y

One end of each strip is beveled, and the projecting rib portions 38, 39, 41 and 42 thereof being primarily atfected.

In use, the strip sections are applied to the face margins of a Wall or door opening as shown in Fig. 8 and Fig. 3. One of the strips, say strip 31, has its 'upper portion secured vertically against the face of studding 43, with the ribs projecting outwardlyv and the beveled end disposed upwardly adjacent the face of header 44. Then the unbeveled end 45 of'strip 32 is disposed so that its unbeveled rib ends 46 and 47 thereof are received in the beveled rib end portions 38 and 39 of previously secured strip 31, as more clearly illustrated in Fig. 9.

This beveled construction provides an arrangement whereby the ground strips can be conveniently and facilely secured, overhead. It will be noted that with one end of overhead section 32 being guided and supported in position by the beveled rib portionsV of vertical section 31, a carpenter is allowed the free use of both his hands in supporting, aligning and nailing the other end of the same section 32 in` position.

It will alsobe noted that this beveled construction allows the side margins of the strips to be abutted, thereby providing a sharp corner arrangement for the plaster formation. The operative side edges of the strips are matched or coplanar thereby providing a ilat plaster surface at the corners.

The opposite side of the door opening can be similarly provided with said plaster ground strips, with the second overhead strip overlapping said first overhead strip 32, as shown in Fig. 8.

Figs. and 1l show another pair of equal-width complementary plaster ground guide strips 48 and 49 modiiied by featuring only a single asymmetrically disposed ribs 51 and 52, respectively; and both ends of each rib being beveled. This narrow construction is especially adapted for walls of narrow width. To allow for convenient end for end interchangeability of these asymmetric sections, both ends of the individual sections are beveled at 53, 54 and 55, 56, respectively. This construction and -application of ground strips to an opening results in mitered joints at the corners.

Both strips are provided with a line of spaced apertures 57, disposed adjacent the ribs thereof, for the reception of nails therein. The apertures are preferably variably spaced at 1A", 1/8, 1/2, 1A, 1%, 1/2 centers, successively repeated. This series of predeterminately spaced apertures in each strip is operative to selectively register as the strips are guided relative to each other.

A rough framed wall opening is an opening such as a door or window opening outlined by side studding and an overhead header, or the like, prepared and ready for the plastering operation. Obviously said framed openings have corner related, side and header studding. The side Surfaces of the studding outlining the opening are the side face margins and the header face margins, respectively.

Figs. 12 to 17 show various modifications of the ground. These cross-sections illustrate a cambered type of ground, having a bent or raised center, the bend being along the longitudinal axis of the strip.

Fig. 12 is a cross-section of a cambered type of ground generally indicated at 61. Being convex, the center por- Ation 62 of the ground, along the longitudinal axis, is

disposed above the side edges 63 thereof. This clearance at the center provides for a spring-like action when the exible ground is drawn to the face of a studding. This construction has a symmetrical cross-section.

Fig. 13 is a cross-section view showing the convex ground of Fig. 12 nailed to the face of a studding 64.

'Ihe spring kaction of said convex ground tensions the side margins of the ground against the edges 65 and 66 of the studding, thereby preventing unwanted displacement therefrom when a plasterer works against the operative edges of the ground. Unwanted displacement of the ground from the studding, during plastering operations, results in plaster becoming lodged between the ground and the studding. Consequently, when the ground is stripped from the studding, after the plaster has dried, a rough unsightly plaster edge is presented; the excess plaster must be removed from the studding; and the plaster thereat is-very vulnerable to being broken away when the finished door frame is being iit into the rough studding frame, as hereinafter described.

The laterally projecting convex side margins 67 and 68 form acute angles 69 and 71, respectively, withthe sides of the studding 64, thereby providing a slight relief, rake or inclined clearance of the plaster to be formed thereagainst. In other words, the plaster along the studding edges will be slightly swept back from the plane of the face of the studding, thereby allowing the usual opposed shingle Wedges, or the like, used when the finished frame -is being positioned within the studdingframe, to be driven across the face of the studding without contact- `ing and breaking away the adjacent plaster portions.

The tension of the ground side margins against the studding edges can be controlled by the distance the nail 6 72 is driven into the studding. Driving that portion of the ground adjacent the nail against' the studding face, obviously provides the maximum tension available. Less tension is provided if the portion of the ground adjacent the nail is maintained spaced from the face of the studding.

A series of predeterminately spaced apertures are provided, as shown in Figs. 6 and 7, operative to selectively register as the strips are guided relative to each other.

Fig. 14 is a cross-section of another cambered type of ground, generally indicated at 73.

This modification comprises a central open faced guide 4rib 70, having downwardly sloped Wings or side margins 74 and 75.

This construction has a symmetrical cross-section. The bottom portion 76 of rib 73 is disposed above the side edges 77.

A longitudinal series of predeterminately spaced apertures are provided, as shown in Figs. 6 and 7, operative to selectively register as the ground strips are guided relative .to each other.

Fig. 15 is a cross-section view showing the cambered ground of Fig. 14 nailed to the face of a studding 78.

When the bottom 76 of the rib 73 is drawn against the face of said studding, the tens-ion of the side margins 74 and 75 against the studding edges 79 and 81, respectively, is obviously at a maximum.

The laterally projecting sloping wings 74 and 75 form acute angles 82 and 83, respectively with the sides of studding 78, thereby providing a slight relief of the plaster formed thereagainst. This modification functions and has the tension advantages as stated in connection with Fig. 13 description, above.

YFig. 16 is a cross-Section of a fur-ther cambered mod- 5 ication, generally indicated at 80. This modification is of prismat-ic construction comprising two 'wing or side members `84 and 85, angularly related, and meeting to forman arris 86.

This bent or cambered construction is of symmetrical cross-section.

When one of such ground strips is superposed over a substantially similar ground strip, the arris formation thereof will guide them lin relative longitudinal movement.

A longitudinal series of predeterminately -spaced apertures are provided at 87, as shown in Figs. 6 and 7, operative to selectively register as the ground strips are guided relative to each other.

This modilication is applied to a studding, and functions thereon, and has the tension and relief advantages as stated in connection with Fig. 13 description, above.

Fig. 17 i-s a cross-section view showing another cambered plaster ground, generally indicated |at 88. This convex modification is of symmetrical cross-section.

When one of such ground strips is superposed over a substantially similar ground strip, the edges thereof are held between t-he fingers to align and guide the ground strips in relative longitudinal movement.

A longitudinal series of predeterminately spaced apertures are provided at 89, Ias shown in Figs. 6 and 7, operative to selectively register as the ground strips are guided relative each other.

This modification is applied to 4a studding, and functions thereon, and has the tension and relief advantages as stated in connection with Fig. 13, above.

The characteristic features of this invention are the provision of a plaster trim guide having a plurality of coacting sections interchangeably useable at random; the provision of a trim guide having open anti-clogging coacting guide ribs; the provision of a trim guide comprising complementary plates having superimposable, slidably-engageable, guide ribs of the open rib, dis/ergingwall type; the provision of cambered ground strips operative to be tensioned against the edges of a studding; the provision of a plaster ground corner structure; and the provision of cambered plaster ground operativeto vide relief of the plaster formed thereagainst.

Obviously, many modiiications and variations of the present invention -are possible lin the l-ight of the above teachings. It is therefore to be understood, that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

What is claimed and desired to be protected by Letters Patent of the United States is: p

l. A plaster trim guide adapted to be secured to a rough frame in a vvall opening, comprising: -a iiat ground strip of sufficient Width to cover the face of a framed opening and to project laterally on opposite sides thereof, said ground strip having a plurality of sections laterally superimposable one over the other and slidably engageable over their entire length, each section having a substantially similar longitudinal open rib disposed 'between said projecting portions and formed from said section, each -rib being correspondingly disposed between the side edge portions of each section, said ribs being mutually -engageable for guiding the sections in relative lengthwise adjustment.

2. A longitudinally adjustable plaster ground adapted to Ibe secured to a lwall opening, comprising: a plurality of ground strips of sufficient width to cover a face of a framed opening and project laterally a predetermined distance on opposite sides thereof to receive plaster against said projecting portions, each strip having a substantially similar longitudinal corrugated rib between said projecting portions, said ribs being mutually engageable for guiding said strips in relative longitudinal displacement, and said ground strips being laterally superposable and slidably engageable over their entire length.

3. A longitudinally adjustable plaster ground adapted to be secured to the margins of `a wall opening, comprising: Ia plurality of equal-width flexible ground strips of suicient width to cover a face of a framed opening and project laterally a predetermined distance on opposite sides thereof to receive plaster against said projecting portions, each strip having a substantially similar longitudinal corrugation disposed between said projecting portions, said ribs being mutually engageable for guiding pro- . said strips in relative longitudinal movement, 4and said ground strips being laterally superposable and slidably engageable over their entire length.

4. A longitudinally adjustable plaster ground adapted to be secured to the margins of a wall opening, comprising: a plurality of equal-width flat thin ground strips of sufficient width to cover a face of a framed opening and project laterally a predetermined distance on opposite sides thereof to receive plaster against said projecting portions, each str-ip having a substantially similar longitudinal open faced guide rib, of convex cross-section disposed intermediate said projecting portions of said strip, said ribs being mutually engageable for guiding said strips in relative longitudinal adjustment, and said ground Strips being laterally superposable and slidably engageable over their entire length.

5. A longitudinally adjustable plaster ground adapted to be secured to the margins of a wall opening, comprising: a plurality of equal-width ground strips of suiicient width to cover a face of a framed opening and project V8. A longitudinally adjustable plaster ground adapted to be secured to a Wall opening, comprising: a plurality of equal-width ground strips of suliicient width to cover a face of a lframed opening and project laterally a predetermined distance on opposite sides thereof to receive plaster against said projecting portions, each having su-bstantially similar longitudinal open rib means disposed between said projecting portions, said rib Vrneans being disposed symmetrically about the longitudinal 'axis of the strip, and said rib means being mutually eugageable for guiding said strips in relative longitudinal displacement, and said ground strips being laterally superposable and slidably engageable over their entire length.

9. A longitudinally adjustable plaster ground adapted to be secured to a wall opening, comprising: a plurality of equal-width ground strips of sufiicient Width to cover a face of a `framed opening and project laterally apredetermined distance on opposite sides thereof to receive plaster against said projecting portions, each having substantially similar open faced guide rib means disposed between said projecting portions, one end of said strip being beveled, and said rib means being slidably engageable for guiding said strips in relation to each other, and said ground strips being laterally superposable and slidably engageable over their entire length.

l0. A longitudinally yadjustable plaster ground adapted to be secured to a wall opening, comprising: a plurality of equal-Width ground strips each .substantially symmetrically cambered about its longitudinal laxis, said strips being laterally superposable on each other and slidably engageable over their entire length for aligned. guidance in relation to each other, and said ground strips being of sufficient width to cover a `face of la `framed opening and project laterally a predetermined distance on opposite sides thereof to receive plaster lagainst said projecting portions.

1l. The apparatus of claim 10 wherein the ground strips are flexible.

l2. The apparatus of claim l0 wherein the groun strips are provided with nail receiving apertures.

13. A longitudinally adjustable plaster ground, cornprising: a plurality of equal-width ground strips carnbered substantially symmetrically about the longitudinal axis of said ground strips, said strips being of -suiiicient width to cover a face of a fnamed opening and project laterally a predetermined distance on opposite sides thereof to receive plaster against said projecting portions, each strip having substantially similar longitudinal corrugation means intermediate said projecting portions of said strips, said corrugation means being slidably engageable for guiding said ground strips in relation to each other.

14. A longitudinally adjustable plaster ground, comprising: a plurality of equal-width ground strips, said strips having a convexity substantially symmetrical about the longitudinal axis of said ground strips, said strips being of suflicient Width to cover aface of a framed opening and project laterally a predetermined distance on opposite sides thereof, to receive plaster against said lprojecting portions, each strip having substantially similar longitudinal corrugation means intermediate said projecting portions of said strips, said corrugation means being slidably engageable for guiding said ground strips in relaterally a predetermined distance on opposite sides thereof to receive plaster against said projecting portions, each having a substantially similar longitudinal corrugation means having convergent sides, `disposed intermediate saidprojecting portions, said .corrugation means being slidably engagea-ble for guiding said strips in relation to ,each other, and said ground strips being laterally superposable and slidably engageable over their entire length. 6. Thevapparatus of claim 5 wherein the strips are iiexi-ble.

7. The apparatus of claim 5 and a series of predeterminedly spaced apertures in each strip, operative to register as the strips are guided relative t0 each other.

kas

lation to each other; and means for securing said ground strips to the margin of a framed opening.

l5. A longitudinally adjustable plaster ground, cornprising: la plurality of equal-width ground stn'psbent substantially along the longitudinal axis thereof, said strips being of suiiicient Width to cover a face of a framed openingl and project laterally a predetermined distance on opposi/te sides thereof to receive plaster against said projecting portions, said ground strips being substantially similar in cross-section and being superposable on each other and slidably engageable for guiding said-ground strips in relation to each other; and means Afor securing Ysaid ground strips to the margin of a framed opening.

16. A longitudinally adjustable plaster ground, comprising: a plurality of equal-width ground strips havng a raised longitudinal central portion and declining side portions adapted to bear against the side edges of a framed opening with said central portion being spaced from the face of said framed opening, said strips being of suiiicient width to cover a face of a framrd opening and project laterally a predetermined distance on opposite sides thereof to receive plaster against said projecting portions, said ground strips being substantially similar in cross-section and being superposable on each other and slidably engageable for guiding said ground strips in relation to each other; and means for securing said ground strips to the margin of a framed opening.

17. A longitudinally adjustable plaster ground adapted to be secured to a wall opening, comprising: a plurality of equal-width ground strips, of sutiicient width to cover the face of a framed opening and project laterally a predetermined distance on opposite sides thereof to receive plaster against said projecting portions, each strip having substantially similar longitudinal corrugation means intermediate the projecting portions of said strips, said corrugation means being slidably engageable for guiding said strips in relation to each other, and said strips being laterally superposable and slidably engageable over their entire length; and a series of predetermined variably spaced nail receiving apertures in each strip, operative to selectively register as the strips are guided relative to each other.

18. A longitudinally adjustable plaster ground adapted entire length, and said strips having substantially square f formed ends.

References Cited in the file of this patent UNITED STATES PATENTS 290,750 Da Cunha Dec. 25, 1883 1,060,810 Blee et al. May 6, 1913 1,416,888 Schumacher May 23, 1922 1,625,637 Abel Apr. 19, 1927 1,762,664 Mott June l0, 1930 2,064,704 Vass Dec. 15, 1936 2,199,318 Landau Apr. 30, 1940 2,438,613 Malthouse a Mar. 30, 1948 2,589,864 Raskin Mar. 18, 1952 2,601,164 Montgomery June 17, 1952 2,686,422 Parrish et al. Aug. 17, 1954 FOREIGN PATENTS 353,494 Great Britain Iuly 17, 1931 368,758 Great Britain Mar. 9, 1932 

